Multi-part telescopic shafts are known from the State of the Art. They have three profile tubes for length-adjustment of the telescopic shaft. The profile tubes are formed such that they have a cross-section that deviates from a circle in order to transmit torque from one profile tube to another profile tube. The profile tubes can have a cross-section in the form of a star or a lemon. In these well-known telescopic shafts the problem arises, how, during the pulling-out of the inner profile tube relative to the intermediate profile tube, the intermediate profile tube can be jointly moved after the inner profile tube has been pulled out by a certain amount relative thereto, to be pulled out relative to the outer profile tube. For this, a pulling wire can be used. The wire is attached at one end on an axial end of the inner profile tube. It is guided therethrough and is attached at its other end at an axial end of the intermediate profile tube. In the retracted condition of the telescopic shaft, the pulling wire lies loosely in the inner profile tube. The wires length is larger than the axial distance of the attachments on the respective profile tubes. Thus, the inner profile tube can be pulled out by a certain amount relative to the intermediate profile tube, before the pulling wire is pulled tight and pulls the intermediate profile tube along. The problem with this coupling is the lack of robustness of the pulling wire. The wire does not withstand the arising loadings after a certain time of use.
DE 33 34 709 C2 illustrates a telescopic shaft with an outer and an inner profile tube. Within the two profile tubes, an inner tie bolt and an outer tie bolt are arranged. The inner and outer tie bolts, respectively, are detachably connected via locking members to one of the profile tubes. The inner tie bolt has diametrically opposed longitudinal slots. A catcher is guided in the slots and is connected to the tie bolt. The catcher passes through the longitudinal slots, when the telescopic shaft is extended in length. A further pulling-out is possible such that the locking members move between the tie bolts and the respective profile tube in the extended locking position. In the extended condition the telescopic shaft cannot transmit a torque.